The advantages of using relay nodes in packets networks to provide quality-of-service assurance in networks that do not provide quality-of-service guarantees are becoming clear, as is taught in U.S. patent application Ser. No. 11/201,892, filed Aug. 11, 2005, entitled “Quality-of-Service Assurance for IP Telephony”. However, the prior art is not always sufficient, and, therefore, the need exists for inventions that help ensure satisfactory quality-of-service in networks that do not provide quality-of-service guarantees.